London, May 5 (IANS): A large study involving over 320,000 patients has found that a drug that has been used worldwide for centuries to treat heart disease, might contribute to an increase in deaths in patients with heart problems.

In this largest-ever review of the effects of digoxin, the researchers found that the drug is harmful for patients with atrial fibrillation or AF (an irregular heartbeat) and also in patients with congestive heart failure or CHF (when the heart's function as a pump is impaired).

"Our analysis, together with evidence from other studies, all point in the same direction: there is harm associated with the use of digoxin," said lead researchers Stefan Hohnloser, professor of cardiology at the J.W. Goethe University in Frankfurt, Germany.

Digoxin is extracted from the foxglove plant (digitalis) and it helps the heart beat more strongly and with a more regular rhythm. It is commonly used in patients with AF and CHF.

However, it can be difficult to use successfully as there is a narrow dose range at which it is effective and beyond which it can be dangerous.

Currently, its use is recommended in guidelines from the US and from the European Society of Cardiology for patients with heart failure and problems with control of the heart's rhythm.

"These recommendations reflect the highly unsatisfactory data basis on which to judge the supposed benefits of digoxin," the authors of the current study wrote.

The researchers conducted a systematic review and meta-analysis of all studies published in peer-reviewed journals between 1993-2014 that looked at the effects of digoxin on death from any cause in AF and CHF patients.

They identified 19 relevant studies that included a total of 326,426 patients (235,047 AF and 91,379 CHF patients).

They found that among patients who were treated with digoxin, there was an overall 21 percent increased risk of death from any cause compared to patients who were not receiving this treatment.

When they looked at the group of AF patients and the group of CHF patients separately, digoxin was associated with a 29 percent and 14 percent increased risk of death from any cause respectively, when compared to patients not receiving the drug.

"Digoxin has been used for decades and even now it is used in approximately one in three AF patients... My personal feeling is that the time of digoxin - particularly as a heart rate-controlling drug in AF - is over. But this needs to be tested in appropriately designed studies," Hohnloser pointed out.

The findings were detailed in the European Heart Journal.